333 research outputs found

    Marketing Privacy: A Solution for the Blight of Telemarketing (and Spam and Junk Mail)

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    Unsolicited solicitations in the form of telemarketing calls, email spam and junk mail impose in aggregate a substantial negative externality on society. Telemarketers do not bear the full costs of their marketing because they do not compensate recipients for the hassle of, say, being interrupted during dinner. Current regulatory responses that give consumers the all-or-nothing option of registering on the Internet to block all unsolicited telemarketing calls are needlessly both over- and underinclusive. A better solution is to allow individual consumers to choose the price per minute they would like to receive as compensation for listening to telemarketing calls. Such a name your own price mechanism could be easily implemented technologically by crediting consumers\u27 phone bills (a method analogous to the current debits to bills from 1-900 calls). Compensated calling is also easily implemented within current don\u27t call statutes simply by giving don\u27t-call households the option to authorize intermediaries to connect calls that meet their particular manner or compensation prerequisites. Under this rule, consumers are presumptively made better off by a regime that gives them greater freedom. Telemarketing firms facing higher costs of communication are likely to better screen potential contacts. Consumers having the option of choosing an intermediate price will receive fewer calls, which will be better tailored to their interests, and will be compensated for those calls they do receive. Giving consumers the right to be compensated may also benefit some telemarketers. Once consumers are voluntarily opting to receive telemarketing calls (in return for tailored compensation), it becomes possible to deregulate the telemarketers—lifting current restrictions on the time (no night time calls) and manner (no recorded calls). And faced with increasing caller resistance, we imagine that survey groups, such as the Gallop Poll, might welcome the opportunity to compensate survey respondents so that they might be able to produce more representative samples

    Devolution revolution? Assessing central-local relationships in England's devolution deals

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    Much recent debate has been generated by the priorities of the newly-elected metro-mayors and their implications for the sub-national governance of England. But the broader question is: will they lead to longer-term change in relationships between central and local government? Mark Sandford, Sarah Ayres, and Matthew Flinders argue that, although not radical, England’s devolution deals may contain the seeds od change

    Observations on the Puddling Behavior of the Canadian Tiger Swallowtail Butterfly, \u3ci\u3ePapilio Glaucus Canadensis\u3c/i\u3e in Northern Michigan

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    (excerpt) The occurrence of puddling behavior in Lepidoptera has been reviewed by M. J. Norris (1936) by J. A. Downes (1973) and by P. H. Adler (1982). Butterflies have been previously reported on mammalian dung, urine, perspiration, saliva, salt, blood, campfire ashes, aphid honeydew, tree sap and animal carrion. The rarity of female puddling in butterflies, particularly the tiger swallowtail (Papilio glaucus) has been recently addressed by two studies (Berger and Lederhouse 1985, Scriber 1987)

    Can the nutrient dynamics of a northern hardwood forest explain variation in its trophic structure?

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    Background/Question/Methods: A time series of Lepidoptera larvae (caterpillar) abundance and biomass in the northern hardwood forests of central New Hampshire, USA, shows large interannual fluctuations in aggregated caterpillar biomass (52-fold variation in mg caterpillars/ 8000 leaves) that were spatially correlated across a regional landscape. Primary production of these mature forests has not varied over this period, and many hundreds of Lepidoptera species share comparatively few host plants. Therefore, interannual changes in nutritional quality of even one host plant species may be capable of generating correlated population dynamics for many species in the Lepidoptera community. We tested the hypothesis that variation in soil nutrient availability influences foliar chemistry and ultimately produces a bottom-up force capable influencing the aggregated biomass of the forest's dominant herbivores.

Results/Conclusions: Over a period of four years, measures of nutritional quality for herbivores in three of the forest's four dominant understory tree species (Acer saccharum, Acer pensylvanicum, and Viburnum alnifolium) displayed considerable variation that was consistent across the landscape. Foliar nitrogen (N) content and two metrics of secondary metabolite concentration—total phenolics and condensed tannin—all varied by up to 20% among years. Resin bag extracts of NH4+, NO2- /NO3- and PO4+ showed soil mineral nutrient availability displayed six-fold variation that was consistent with the pattern in foliar N, and a whole tree in situ fertilization experimental manipulation produced rapid effects on foliar chemistry. Finally, variation in the forewing lengths of free-flying moths showed an interannual concordance among species within the group of early season feeders that was also consistent with patterns in foliar quality—suggesting collections of species experience correlated variations in larval growth performance.
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    Extreme climatic events affect populations of Asian chestnut gall wasps, Dryocosmus kuriphilus, but do not stop the spread

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    [EN] Global climate change affects the frequency of extreme weather events that can influence plant–insect interactions. We evaluated how the late-spring frost and severe drought that occurred in Spain in 2017 affected interactions between the invasive gall insect, Dryocosmus kuriphilus, and the native tree, Castanea sativa. We assessed effects on insect survival, fertility, population growth, and effects through changes in tree palatability and in other pests and pathogens. Late-spring frost reduced D. kuriphilus to 25–40% of previous abundance. Wasp populations recovered rapidly (>7-fold in 3 years), consistent with density-dependence in population dynamics. Larvae affected by freeze or drought were smaller. Female fecundity was affected by the freeze 1 year later. Late-spring frosts and severe drought affected leaf size and physiology. Water content was higher within galls, but nitrogen was higher within galls in non-freeze plots after weather conditions improved. Freezing also influenced the secondary chemistry of leaves. Phenol concentrations were lower, and terpenes higher, in frozen plots, while condensed tannins remained the same. Condensed tannins were reduced to half in the drought year. Freezing had limited effects on damage from other pests and pathogens. Our work expands understanding of how climate and weather affects forest pestsSIThis work was supported by FEDER/Spanish Ministry of Economy and Competitiveness Research (Grant AGL2016-76262-R). Diana Blanco, Elva Rico, and Naidu Lombardero provided assistance in the field and in the lab. The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this pape

    Extreme climatic events affect populations of Asian chestnut gall wasps, Dryocosmus kuriphilus, but do not stop the spread

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    1 Global climate change affects the frequency of extreme weather events that can influence plant–insect interactions. 2 We evaluated how the late-spring frost and severe drought that occurred in Spain in 2017 affected interactions between the invasive gall insect, Dryocosmus kuriphilus, and the native tree, Castanea sativa. We assessed effects on insect survival, fertility, population growth, and effects through changes in tree palatability and in other pests and pathogens. 3 Late-spring frost reduced D. kuriphilus to 25–40% of previous abundance. Wasp populations recovered rapidly (>7-fold in 3 years), consistent with density-dependence in population dynamics. 4 Larvae affected by freeze or drought were smaller. Female fecundity was affected by the freeze 1 year later. 5 Late-spring frosts and severe drought affected leaf size and physiology.Water content was higher within galls, but nitrogen was higher within galls in non-freeze plots after weather conditions improved. 6 Freezing also influenced the secondary chemistry of leaves. Phenol concentrations were lower, and terpenes higher, in frozen plots, while condensed tannins remained the same. Condensed tannins were reduced to half in the drought year. 7 Freezing had limited effects on damage from other pests and pathogens. 8 Our work expands understanding of how climate and weather affects forest pestsThis work was supported by FEDER/Spanish Ministry of Economy and Competitiveness Research (Grant AGL2016-76262-R)S

    Host Use Patterns by the European Woodwasp, Sirex noctilio, in Its Native and Invaded Range

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    Accelerating introductions of forest insects challenge decision-makers who might or might not respond with surveillance programs, quarantines, eradication efforts, or biological control programs. Comparing ecological controls on indigenous vs. introduced populations could inform responses to new introductions. We studied the European woodwasp, Sirex noctilio, which is not a pest in its native forests, is a serious invasive pest in the southern hemisphere, and now has an uncertain future in North America after its introduction there. Indigenous populations of S. noctilio (in Galicia, Spain) resembled those in New York in that S. noctilio were largely restricted to suppressed trees that were also dying for other reasons, and still only some dying trees showed evidence of S. noctilio: 20–40% and 35–51% in Galicia and New York, respectively. In both areas, P. sylvestris (native to Europe) was the species most likely to have attacks in non-suppressed trees. P. resinosa, native to North America, does not appear dangerously susceptible to S. noctilio . P. radiata, which sustains high damage in the southern hemisphere, is apparently not innately susceptible because in Galicia it was less often used by native S. noctilio than either native pine (P. pinaster and P. sylvestris ). Silvicultural practices in Galicia that maintain basal area at 25–40 m2/ha limit S. noctilio abundance. More than 25 species of other xylophagous insects feed on pine in Galicia, but co-occurrences with S. noctilio were infrequent, so strong interspecific competition seemed unlikely. Evidently, S. noctilio in northeastern North America will be more similar to indigenous populations in Europe, where it is not a pest, than to introduced populations in the southern hemisphere, where it is. However, S. noctilio populations could behave differently when they reach forests of the southeastern U.S., where tree species, soils, climate, ecology, management, and landscape configurations of pine stands are different

    Defensive patterns of chestnut genotypes (Castanea spp.) against the gall wasp, Dryocosmus kuriphilus

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    Plants draw from various genetically controlled defenses to protect against herbivores and pathogens. The efficacy of alternative defenses can vary with the biology and phylogeny of the enemy. Dryocosmus kuriphilus, an invasive gall maker native to China, has become one of the main pests of chestnut trees around the world. We studied genetic variation in resistance and susceptibility to D. kuriphilus within a replicated blocked planting of 12 chestnut genotypes established in Galicia, Spain in 2004. We found very high genetic variation in susceptibility to D. kuriphilus. We evaluated if the variation was due to host selection by the wasp, differential efficacy of inducible defenses in the trees, or variability in susceptibility of the plant to manipulation by the gallmaker. We assessed host selection by counting number of eggs laid by females in tree buds and comparing preferences with phytochemistry. We also measured inducible changes in phytochemistry within and around galls, gall physical characteristics, parasitism, and insect fitness. The effective defense mechanisms in resistant genotypes involved (1) hypersensitive reactions to eggs or neonates within buds and (2) early precise abscission of nascent galls from expanding leaves. Surprisingly, the genetic resistance to D. kuriphilus of the chestnut genotypes we tested was not related to phenols, terpenes, and primary nutritionSIThis work was supported by FEDER/Spanish Ministry of Economy and Competitiveness (Research Grant AGL2016-76262-R)

    Impact of Minimum Winter Temperatures on the Population Dynamics of Dendroctonus Frontalis

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    Predicting population dynamics is a fundamental problem in applied ecology. Temperature is a potential driver of short-term population dynamics, and temperature data are widely available, but we generally lack validated models to predict dynamics based upon temperatures. A generalized approach involves estimating the temperatures experienced by a population, characterizing the demographic consequences of physiological responses to temperature, and testing for predicted effects on abundance. We employed this approach to test whether minimum winter temperatures are a meaningful driver of pestilence from Dendroctonus frontalis (the southern pine beetle) across the southeastern United States. A distance-weighted interpolation model provided good, spatially explicit, predictions of minimum winter air temperatures (a putative driver of beetle survival). A Newtonian heat transfer model with empirical cooling constants indicated that beetles within host trees are buffered from the lowest air temperatures by approximately 1-4 degrees C (depending on tree diameter and duration of cold bout). The life stage structure of beetles in the most northerly outbreak in recent times (New Jersey) were dominated by prepupae, which were more cold tolerant (by \u3e3 degrees C) than other life stages. Analyses of beetle abundance data from 1987 to 2005 showed that minimum winter air temperature only explained 1.5% of the variance in interannual growth rates of beetle populations, indicating that it is but a weak driver of population dynamics in the southeastern United States as a whole. However, average population growth rate matched theoretical predictions of a process-based model of winter mortality from low temperatures; apparently our knowledge of population effects from winter temperatures is satisfactory, and may help to predict dynamics of northern populations, even while adding little to population predictions in southern forests. Recent episodes of D. frontalis outbreaks in northern forests may have been allowed by a warming trend from 1960 to 2004 of 3.3 degrees C in minimum winter air temperatures in the southeastern United States. Studies that combine climatic analyses, physiological experiments, and spatially replicated time series of population abundance can improve population predictions, contribute to a synthesis of population and physiological ecology, and aid in assessing the ecological consequences of climatic trends
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